Electric signal



(Model) 2 Sheets-Sheet 1.

H. R. MILLER. Electric Signal.

NO. 237,576. L Patented Feb. 8,1881.

Fig. 2.

-2 ShGGtB-ShGBt 2.

(Model) H. R. MILLER.

'Blectricfiignal. I

Patented Feb. 8, 1881..

741M lZ/M ",PETERS. FHOTO-LITHOGFIAPHER; WASHINGTON. D4 C.

UNITED STATES PATENT Erica.

HOMER R. MILLER, OF FRAMINGHAM, MASSACHUSETTS.

ELECTRIC SIGNAL.

SPECIFICATION forming part of Letters Patent No. 237,576, dated February 8, 1881.

Application filed September 28, 1880.

To all whom it may concern:

Be it known that I, HOMER R. MILLER, of Framingham, in the county of Middlesex and State of Massachusetts, have invented a new and useful Improvement in Electric Signals; and I do hereby declare that the following is afull, clear, and exact description of the same.

My invention relates to electric signals of the class, principle, and design to be used in connection with telephones. It is an improvement upon an apparatus which is the subject.

of an application filed by me in the United States Patent Office on the (5th day of April, 1880.

The lHJPIOVGIHBIlll relates, first, to the improved shunting devices and their arrange: ment in the line; second, in an improved key mechanism; and, third, in subordinate details relating to these principal points.

In the accompanying drawings the machine is represented in Figure l in perspective. Fig. 2 is a perspective view of the opposite side. Fig. 3 is a side elevation with parts in section. Figs. 4 and 5 represent the improved key mechanism detached. Fig. 6 represents the main shunting device, and Fig. 7 a modification of the same.

The magnets, bell, and working parts of the machine are mounted upon a metallic frame, A. The main-line magnetB is insulated upon the frame of the machine, and is held by a screw passing through the frame, as shown at a. The bell-magnet is in a similar manner mounted upon the frame directly above the main magnet, and the bell is mounted upon a standard directly over its magnet. The armature c of the main-line magnet is supported upon pivots in the frame, and carries a slender rod or bar, d, which operates the pawl-andratchet mechanism. The armature of the bellmagnet is mounted upon standard 0' by means of pivots, and carries a bell-hammer,l),adapted, when the armature is drawn up to the magnet, to strike the bell E.

The main shunting devices, by means of which any instrumentin the circuit may be brought into call at the will of the operator at any other station, are shown in connection with the pawl-and-ratchet mechanism. Upon the shaft of this ratchet-wheel, and concentric therewith, is a wheel, k, on the periphery of which is an insulated spot, 1, Figs. 3 and 6,

(ModeL) made by the insertion of a piece of non-conducting material. Bearing against the periphery of this wheel is a light spring-standard, m, the lower end of which is fixed to an insulating-block, a, connected to the frame. This standard at is in electrical connection with the main line, as is hereinafter fully explained.

The pawl-and-ratchet mechanism is of an improved form, andis designed to obtain the same amount of movement of the ratchetwheel with only one-half the movement of the armature, whereby greater rapidity of action is gained and less battery-power required. The wheel is a ratchet-wheel of ordinary form; but instead of the ordinary pawl, working on one side of the wheel, I-have provided two, which work in opposite directions, and thus obtain a movement of the wheel with the backward as well as forward movement .of the armature. The wheel revolves in the direction of the arrow, Fig. 3. The pawls are both pivoted in the rod or bar d, one above and the other below. The upper pawl, e, is arranged tangentially to the wheelf on the upper edge, and is formed with a plain end adapted to fit against the radial faces of the teeth, so as to push the wheel, when the standard is moved toward the wheel, by the backward movement of the armature, to which it is attached. The lower pawl, e, is tangential to the lower face of the wheel, and is provided with a hook adapted to catch over the teeth of the ratchetwheel. and bear against their radial faces, so as to draw upon said teeth and partially turn the wheel, when the armature carrying the bar 11 is drawn up. It will be observed, from the construction shown, that the pawls move simultaneously and in the same direction, but act alternately and in opposite directions. While the upper pawl is pushing the lower is slipping over a tooth, into engagement with which it falls when the upper has reached the limit of its movement. When the armature is drawn up, and the reverse motion of the pawls occurs, the lower pawl draws upon the wheel, giving it a partial turn,,while the upper is slipping over a .tooth, in the manner shown above in connection with the lower. In this action of the pawls and ratchet-wheel there is manifestly a movement of both pawls and wheel, and the movement of the wheel both above and below, servesequally to bring the tooth to pass over the hooked end thereof.

bearing-face of the pawl toward the bearingface of the tooth.

The parts should be so adjusted that when the armature carrying the bar (1 is drawn up the pawls shall both be in contact with the radial faces of the teeth, as shown in Fig. 3. One pawl or both are therefore always in contact with the radial face of a tooth or teeth, and the wheel is turned and held against backward movement without any other holding device. Vhen in operation theliability is, when the armature is drawn up, that the momentum of the wheelfshould carry it in advance of the movement of the pawls and more than the space of a single tooth, thereby impairing the accuracy of the instrument. To prevent this I have set a post, q, directly under the pawl c, Fig. 3, and cut away the edge of the bar above it, as shown at q. The curved recess q is so arranged in relation to the post q and the teeth of the ratchet-wheel that when the armature falls back and advances the pawls toward the wheel the lower pawl, 0, shall ride freely over the tooth; but when the armature is drawn up the pawl is drawn back with the inclined part of q approaching more nearly to the post q, which prevents the pawl from moving far enough downward to permit the It is plain that the pawls must be held to the wheel with just suificient force to maintain contact. Any suitable spring may be employed for the purpose. A convenient and simple form of spring is shown in Fig. 3. The ends of the pawls extend a short distance to the rear of their pivots, and are curved outwardly, so that the spring 1' (one end of which rests on the upper and one on the lower) presses both toward the wheel. The armature of the main magnet is drawn back with required force by means of a spring, i, the tension of which is adjusted by a springor bar, I, to which it is connected, the spring or bar Ibeing drawn back by set-screw 4.

On the shaft of the ratchet-wheel, and concentric therewith, is placed a smaller metal wheel, 7;, in electrical connection with the frame. It is made smaller than the ratchetwheel, in order that the pawls c 0, working upon the periphery of the larger ratchet-wheel, may gain in leverage, and thus more easily overcome the friction of the light spring 122, the end of which presses constantly against the periphery of the wheel 7;. When thus pressing it brings the wheel into the mainline circuit, except when the end of the spring m rests upon an insulatin g-spot, 1, Fig. 3. The spring on is fixed to and insulated upon a block, a, attached to the frame, and is connected to the main-line wire 6. This spring m, in connection with the insulated spot upon the wheel, constitutes the first shunting device in the main line, the operation of which is explained hereinafter in connection with the general operation of the apparatus.

The wheel Ir is represented detachedin Fig. 6. An equivalent device is shown in Fi 7,

in which the wheel is provided with a notch instead of insulated spot, and the spring at has a spur fitted to the notch. The spring on in this form, as in the other, is insulated on block n, but is not connected to the wire. Connection with the wire is obtained through spring m, also insulated on block n and connected to the main-line wire 6. When the spur is in the notch there is a space between the upper ends of m and m, and the ircuit is broken, but closed when the spur rests on the periphery, and m is thereby forced back into contact with 'm. This modification will operate equally as well as the other, except that slightly more battery force is required to move the spur out of the notch.

A second shunting device operates in connection with the armature of the bell-magnet. It consists of a spring, h, fixed upon the insulating-block a, and also connected to the main-line wire 6. The spring is placed on one side of the frame, as shown more clearly in Fig. 1. The upper and free end rests upon an insulating-block, n, on the end of the armature when said armature is thrown back. \Vhen, however, the armature of the bell-magnet is drawn up, the spring h, following it, moves to the metal stud 1), (preferably of platinum,) which is in electrical connection with the frame. After the spring it reaches the stud it remains in contact unremoved by the return of the armature. It will be observed, therefore, that the second shunt, being within the main-line wire and between the primary shunt and the connection of the bell-loop with the main line, establishes for an instant the circuit in the main line broken by the contact of the first shunting-spring with the insulating-spot on the wheel; but whether this be open or closed the connection of the loop, including the bell-magnet, is permanently complete. The special operation of these parts is also set forth fully in connection with the description of the operation of the whole.

The improved key mechanism shown detached in Figs. 4 and5 is represented, in part, in Fig. 1, the ends of the lever projecting for engagement with the spring F. The same is shown in connection with Fig. 3 with the wires attached, the parts, however, being moved out of place for convenience of illustration.

A defect occurs in the use of the ordinary key in connection with apparatus of the class herein described. Uniformity of actions in the signaling apparatus depends largely upon uniformity in the pressure applied to the key, which brings the parts into contact to make and break connections. The difference between a firm positive pressure and a weak slight touch is sufficient to impair the operations of the apparatus. 'Where the contact is obtained by direct pressure applied by the hand it will generally be more or less variable. The object of this part of my invention is to obtain a positive contact, uniform and certain under all circumstances.

Within the frame, at one end, 1 pivot a lever, G, by means of a screw, 8, so that the arms t 15 project outside the frame and loosely embrace the spring F, so that a certain amount of movement of said spring will give the necessary throw to the lever. The inner end of lever G is provided with a friction-wheel and bears against the face of a spring-standard, H. This standard is [formed with a sharp bend projecting toward the lever and in its path, so that as the lever is pressed down by the spring F the opposite end rises; the friction-roller runs up the lower incline, pressing the spring back until the wheel has passed the apex of the bend, when the elasticity ofthe spring, reacting upon the wheel, presses with the opposite or upper face of the incline and forces the lever upward, completing the movement begun by the hand. All that is required of the hand is that it shall press the key sufficiently to cause-it to pass the bend in the standard. Less force applied to the spring will not cause the lever to pass the bend and will not break contact.

Upon the lever G is pivoted by the same pivot, s, a loose plate, J. One end is rounded on a curve struck from the center of the pivot, and the other is provided with two arms, at M, which are bent laterally, so as to inclose the inner end of the lever Gr, butloosely, as shown in Fig. 4, to give a certain amount of play to the plate or to the lever within the arms of the plate. There is a sleeve upon the screw 8, on which the lever and plate directly turn, and which secures freedom of movement.

On the outer or rounded end of the plate J rests a spring, '0, which is insulated on the frame, and is connected to section 11 of the main-line wire. The key mechanism being connected to the frame by wire 10, when the insulated spring '0 is in contact with the metallic part of the rounded face of plate J the connection is made through the line. This happens when the key-spring F is raised, as shown in full lines in Fig. 4; but when the key-spring is depressed, as shown in dotted lines, same figure, the contact end of lever 11 rests on an insulating-spot, v, and the connection is broken. It will be observed, therefore, that the contact which makes and breaks connection is caused by the pressure of the spring 11 against the rounded edge of plate J, and that the last part of the movement of the lever, which brings the insulating-spot 1) under the contact end of the spring v, is effected by the reaction of the spring-standard H. The contact, if made at all, must therefore always be precisely the same, regardless of the amount of force applied to the spring F, provided only that it shall be sufficient to move the lever G past the bend of the spring-standard.

The general direction of the wires and other electrical connections is shown in Fig. 3. I

Supposing the post K to be in electrical connection with the positive pole of the battery, the direction of the current will be through section 5 of the main line, which section is connected to one end of the coil of the main mag-- net. From the other end of said coil the wire 7 runs to the junction of wires 8 and 6. Of these 8 is connected to one end of the coil of the bell-magnet, the other end of which is connected by the wire 9 to the frame. Through this (provided the connection of wire 6 is broken) the current passes to wire 10, through the key and wire 11, to post L, at which the other end of the main line is attached. As before stated, wire 6, which is a continuation of 7, runs to the insulated spring m, which, when in connection with the metallic face of the wheel is, is in electrical connection with the frame, and through that with the wire 10 and main line. When spring m is on the insulated spot 1 this connection is broken and the current is forced from this shorter circuit into the loop at 8, which includes the bellmagnet.

It will be readily understood that the insulated spot on the wheel is arranged to correspond on each machine to the number of the station, and that the wheel 70 is turned by successive impulses through the line, each impulse tnrning the ratchet f the space of one tooth. The operator, therefore, at any other station sending the proper number of impulses, brings the insulated spot of any given machine under the spring m, and thus breaks the main line. This, as before explained, forces the current through the loop and operates the bell-armature, drawing it up, and with it the hammer, against the bell. This movement, as explained, brings the spring h into contact with the stud p and makes again the mainline connection, thereby diverting the current for an instant sufficiently from the loop to allow the bell-magnet armature to fall back, which breaks the connection of h and p in the main line and restores the current in the loop. Thus the bell is rapidly rung as long as the spring at rests on the insulated spur l of the wheel is. The intervals of connection in the main line between it and p are not suflicient to work the armature of the main-line magnet. The connection of the loop with the main line is never broken. The breaking of the connection at 1 on wheel 70 (which is the first shunt) gives impulse to the bell-magnet armature, and the rapid breaks at the second shunt cause the strokes of the bell as long as the spring 112 is on the insulating-spotin fact, until it is removed by the operator; but when the connection with the wheel is closed the hell cannot be rung.

A dial, M, is provided, over which the indexfinger on the end of the ratchet-wheel shaft moves and indicates the position of the insulating-spot.

Having thus described my invention, what I claim as my invention is- 1. An electrical signal consisting of an electro-magnet situated in the main-line circuit and adapted to operate any shunting device in the line by predetermined movements of the key, in combination with a second electromagnet situated in a continuous loop permauently connected to the main line, and with a second shunting device in the main line, operated by the bellmag'net armature and adapted to make and brealc connections in the main line, whereby the bell is made to ring continuously until the first shunting device is operated, substantially as described.

2. The combination of the main magnet, pawl-and-ratehet mechanism, and shunting devices connected therewith with the bell-magnet located in the loop, and with the spring h, connected to the main line between the main shunting device and loop and adapted to bear upon an insulating-block on the armature of the bell-magnet, and to operate in combination with the stud p, as set forth.

3. In an electrical signaling apparatus, the combination of the pivoted l6 Y-l6\(31,2t spring adapted to resist the first and to accelerate the last part of the movement of said key-lever, of 20 a plate having insulated spot thereon and moved by said key-lever and of a spring-connection bearing upon the face of said plate, all as and for the purposes set forth.

4. The combination of the lever G, plate J, having insulated spot and spring 4; with the spring-standard H and mechanism for operating the lever, substantially as described.

In testimony whereof I have signed my name to this specification in the presence of two sub- 0 scribing witnesses. I

HOMER 1t. MILLER.

Witnesses GEORGE U. TRAVIS, GEO. W BrenLow. 

